Thesis Format
Monograph
Degree
Master of Science
Program
Anatomy and Cell Biology
Supervisor
Shepherd, Trevor G.
Abstract
Epithelial ovarian cancer is the most lethal gynaecological cancer in the developed world. Spheroids, multicellular aggregates that disseminate into the peritoneal cavity are mediators of disease progression. Autophagy supports spheroid survival and is linked to chemoresistance. This study investigates inhibition of unc51-like-kinase 1 (ULK1), an autophagy regulator, using MRT68921 and its combination with tyrosine kinase inhibitor afatinib. Immunoblotting confirmed MRT68921 inhibits ULK1 activity at low micromolar concentrations, reducing phosphorylation of Beclin1 Ser30 within 30 minutes, and for 96 hours. Spheroids stably expressing mCherry-eGFP-LC3B demonstrated that MRT68921 inhibits autophagic flux, while afatinib increases it. Increased LC3II/I detected via immunoblotting is consistent with afatinib-induced autophagy. Synergy Finder identified synergistic combinations and spheroid viability assays demonstrated that MRT68921 drives reduced viability in spheroids. Ascites-derived organoids were sensitive to MRT68921 and afatinib, with many treatment conditions reducing viability by 50% or more. These findings suggest a novel therapeutic strategy that warrants further evaluation.
Summary for Lay Audience
Ovarian cancer bears the highest mortality rate of all gynaecological cancers in the developed world. Due to the lack of clear symptoms, this disease is often detected at late stages when it has already spread. Although many women initially respond well to chemotherapy, most experience a relapse where the cancer returns and no longer responds to treatment. Once this happens, there are very limited treatment options, highlighting the need for new treatment strategies. Ovarian cancer spreads when cells break off from the primary tumour and cluster together to form “spheroids”. These spheroids are important in disease progression as they travel into the abdomen, attach to organs, and form new tumours. Our research group has found that spheroids rely on “autophagy” for survival. Autophagy, which translates from Greek to “self-eating”, involves cells degrading and recycling their own components. Importantly, autophagy helps spheroids evade chemotherapy, making spheroids difficult to treat. This process is regulated by a molecule called ULK1. Here, we are testing a drug called MRT68921 to see if it blocks ULK1 function and autophagy. We found that MRT68921 can indeed block ULK1 and autophagy in ovarian cancer spheroids, so we then added another anti-cancer drug called afatinib to see if it could have even better cancer cell-killing effects. We found that MRT68921 and afatinib resulted in synergistic effects, meaning these drugs work better together than alone. These findings suggest that MRT68921 could be a promising treatment for ovarian cancer by targeting ULK1 and autophagy. We also show that combining it with afatinib may improve treatment effectiveness. Given the lack of treatment options for when ovarian cancer relapses, it is important to continue to investigate this new treatment strategy to improve outcomes for patients with ovarian cancer.
Recommended Citation
Johnston, Tiffany P A, "Investigating Synergistic Combinations of MRT68921 and Afatinib as a Therapeutic Strategy in Epithelial Ovarian Cancer" (2024). Electronic Thesis and Dissertation Repository. 10349.
https://ir.lib.uwo.ca/etd/10349